class_docstr: Sentence-level relation extraction dataset
code: def __getitem__(self, index):
      item = self.data[index]
      seq = list(self.tokenizer(item, **self.kwargs))
      res = [self.rel2id[item["relation"]]] + seq
      return [self.rel2id[item["relation"]]] + seq
  
imports: import torch
  import torch.utils.data
  import os, random, json, logging
  import numpy
  import sklearn.metrics
label_desc: Use image node_id 3 for calling the SentenceREDataset obj's underlying member method code with example usage: obj.__getitem__(index) and returns: unknown